JPH0724618Y2 - Internal combustion engine for hand-held work machines with manual and automatic starters - Google Patents

Description

TECHNICAL FIELD The present invention relates to an internal combustion engine for a portable work machine with a manual and automatic starter.

2. Description of the Related Art For portable work machines such as brush cutters, chain saws and backpack-type control machines, it is an important requirement to make the machine body compact and lightweight. The conventional internal combustion engine for portable work machines has a manual starter such as a recoil type starter or a mainspring starter as a starter for starting it, but in recent years, those with an automatic starter have been commercialized. There is also proposed an internal combustion engine equipped with both a manual starter and an automatic starter to facilitate starting, but such a conventional internal combustion engine is complicated in structure and large in size, and is not suitable for a portable work machine. , It takes time to assemble and maintain the internal combustion engine, and it is difficult to standardize the structure regardless of the model for mass production, and it is not compatible with the existing engine equipped with only a manual starter. There were inconveniences such as the difficulty of modifying the existing machine.

Therefore, the present invention provides both a manual starter and an automatic starter for convenience in use, and these devices can be compactly arranged to facilitate assembly and maintenance. Thus, it is an object of the present invention to provide an internal combustion engine for a portable work machine equipped with a manual and automatic starter, which is applicable to various models and is compatible with existing engines.

Means for Solving the Problems That is, an internal combustion engine for a portable working machine with a manual and automatic starter according to the present invention is detachably attached to an internal combustion engine and is coaxial with a crankshaft of the internal combustion engine. The ratchet wheel is rotatably supported in the starter case, a flange member is attached to the crankshaft, and the ratchet portion of the ratchet wheel is drivingly connected to a centrifugal pawl pivotally mounted on the flange member. An automatic starter is disposed on the first and the output gears driven by the automatic starter are independently rotatably supported on the ratchet wheel via a first one-way clutch device, and a second gear is mounted on the ratchet wheel. A manual starter is independently rotatably supported via a one-way clutch device, and an external drive end is formed by projecting a tip end portion of an output shaft of the automatic starter to the outside of the starter case. To do.

Therefore, both the manual starter and the automatic starter are arranged in the starter case so that the internal combustion engine can be started by the manual starter and the automatic starter.

Embodiment Next, the present invention will be described based on an embodiment of the drawings.

The illustrated embodiment is an example suitable for use in, for example, a portable work machine such as a brush cutter, and the internal combustion engine 1 has one output end (not shown) of its crankshaft 2 through a transmission device such as a centrifugal clutch. Is connected to the cutting blade of the working machine, and the internal combustion engine 1 is driven to rotate the crankshaft 2 so that the cutting blade can be driven to perform work.

In the internal combustion engine 1, a starter case 4 is detachably attached to the other end of the crankshaft 2 on the side of the other end 3 with a screw or the like. The starter case 4 is made of a suitable material such as synthetic resin, and a central shaft 6 extending coaxially from the end of the case 4 toward the crankshaft 2 is integrally provided. The central shaft 6 rotatably supports a sleeve-shaped ratchet wheel 7 extending in the axial direction. The ratchet wheel 7 is held immovably in the axial direction by a screw 8 and a washer 9 which are screwed onto the tip of the central shaft 6. The claw wheel 7 has three claw parts formed on the outer periphery of the claw wheel 7 while being separated from each other in the axial direction.
10 and 11 and 12 and two bearing parts 13 and 14 are formed, these claw parts 10, 11 and 12 and bearing parts 13 and 1
Each of the four acts as described below.

A flange member 15 is attached to the end portion 3 of the crankshaft 2. The flange member 15 has a plurality of centrifugal pawls 16 pivotally attached to the flange member 15 at positions eccentric outward in the radial direction. The centrifugal claw 16
Is biased by a spring 5 and engages the first pawl portion 10 of the pawl wheel 7. This claw portion 10 and centrifugal claw 16
Is configured to transmit the rotational force of the ratchet wheel 7 in the operating direction of the crankshaft 2 to the crankshaft 2, but to block the transmission of the rotational force of the ratchet wheel 7 in the opposite direction. There is.

Further, the ratchet wheel 7 supports a manual starter 17. The manual starter 17 is a recoil type starter in the illustrated embodiment, and includes a recoil drum 18 independently rotatably supported on the first bearing portion 13 of the ratchet wheel 7, and the recoil drum.
A recoil rope 20 wound in a circumferential groove 19 of 18 and having a tip portion extended to the outside of the starter case 4, and the recoil rope 20 rotating the recoil drum 18 to form the circumferential groove.
A mainspring 21 wound around 19 and a second claw portion 12 of the ratchet wheel 7
The second pawl portion 12 and the pawl 22 apply the rotational force of the recoil drum 18 in the rotational direction of the crankshaft 2 to the pawl wheel 7. It is configured as a one-way clutch device that transmits but blocks the transmission of rotational force in the opposite direction.

The starter case 4 is integrally formed with a downward protruding portion 23, and the electric motor 25 of the automatic starter 24 is fixed to a side portion of the downward protruding portion 23 so as to be close to the lower side of the internal combustion engine 1. Are arranged. The output shaft 26 of the electric motor 25 is rotatably supported across the inside of the downward projecting portion 23 of the starter case 4 in the same direction and in parallel with the end portion 3 of the crankshaft 2. A tip portion 27 of the output shaft 26 protruding from the overhanging portion 23 to the outside forms an external drive end by a battery drill or the like.

Further, the automatic starter 24 has a small gear 28 fixed to the output shaft 26 in the downward protrusion 23,
28 is an intermediate shaft rotatably supported by the starter case 4.
It meshes with an intermediate large gear 30 fixed to 29. The intermediate large gear 30 is integrally formed with an intermediate small gear 31, and the intermediate small gear 31 is independently rotatably supported on the second bearing portion 14 of the ratchet wheel 7. It meshes with the gear 32. The output gear 32 is the third pawl portion of the ratchet wheel 7.
A spring-biased pawl 33 engaging with 11 is pivotally mounted. The pawl portion 11 and the pawl 33 apply the rotational force of the output gear wheel 32 in the rotational direction of the crankshaft 2 to the pawl wheel 7. To the
It is configured as a one-way clutch device that blocks the transmission of rotational force in the opposite direction. Also, the small gear
28, the intermediate large gear 30, the intermediate small gear 31, and the output large gear 32 are
A gear reduction device for reducing the rotational force of the electric motor 25 and transmitting it to the ratchet wheel 7 is configured, and the output large gear 32 constitutes an output gear of the gear reduction device.

The flange member 15 of the crankshaft 2 has a magnet 34 of a generator fixed to an outer peripheral portion thereof, and the generator fixed to a portion of the starter case 4 near the outer peripheral portion of the flange member 15. The child winding 35 is arranged. Therefore,
The magnet 34 generates a current in the stator winding 35 during the rotation of the crankshaft 2, and the current is generated by the automatic starter 24.
The battery is supplied to a battery charger, an illumination lamp, or the like, which is not shown. In this way, the flange member 15 of the crankshaft 2 is
It also functions as a rotor of the generator, and the portion between the flange member 15 and the electric motor 25 of the starter case 4 can be used as a mounting portion for the stator of the generator, which contributes to downsizing of the device. To do.

With the above-described structure, when the internal combustion engine 1 is started by the manual starter 17, the recoil rope 20 is pulled to the outside of the starter case 4 against the action of the mainspring 21, and the recoil drum 18 is rotated. The force is transmitted to the crankshaft 2 via the ratchet wheel 7 and the flange member 15 to rotate the crankshaft 2 and start the internal combustion engine 1. At this time, the output large gear 32 of the automatic starter 24 is stopped by the one-way clutch device of the third pawl portion 11 and the pawl 33 of the pawl wheel 7 because the rotational force for driving is cut off. When the rotation of the crankshaft 2 increases, the centrifugal claw 16 of the flange member is automatically disengaged from the first claw portion 10 of the ratchet wheel 7 by the centrifugal force.

Separately from this, when the internal combustion engine 1 is started by the automatic starter 24, the electric motor 25 is energized to rotate its output shaft 26, and this rotational force is transmitted to the ratchet wheel 7 via the gear reduction device described above. To rotate the ratchet wheel 7, thereby rotating the crankshaft 2 to start the internal combustion engine 1. At this time, the recoil drum 18 of the manual starter 17 is stopped by the one-way clutch device of the second claw portion 12 and the claw 22 of the ratchet wheel 7 because the rotational force for driving is cut off.

In this way, the internal combustion engine 1 can be started by either the manual starter 17 or the automatic starter 24. Also, it is understood that an internal combustion engine that uses a recoil type starter as the manual starter 17 can be made to be a manual / automatic dual type simply by replacing the recoil type starter part without modifying the other parts. Will be done.

Effects of the Invention With the configuration of the present invention described above, the present invention is suitable as an internal combustion engine for a portable work machine, in which both a manual starter and an automatic starter are arranged in a starter case to make the structure compact. It is easy to assemble and maintain the internal combustion engine, compatible with the conventional starter without changing the structure of the crankshaft, and standardized the structure regardless of the model for mass production. Can be realized. Further, in the case where both the automatic starter and the manual starter fail and fall into a state where the start is impossible, it is possible to enable the start by using a battery drill or the like at the external drive end. Play.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of an internal combustion engine for a portable work machine with a manual and automatic starter according to the present invention, and FIG. 2 is an end view of the essential part of the internal combustion engine of FIG. Figure 3 is the first
It is a front view of the part of a figure. 1 ... Internal combustion engine, 2 ... Crankshaft, 4 ... Starter case, 7 ... Claw wheel, 10 ... Claw portion, 15 ... Flange member,
16 …… Centrifugal claw, 17 …… Manual starter, 24 …… Automatic starter,
32 …… Output gear, 11,33 …… First one-way clutch device, 12,22 …… Second one-way clutch device.

Claims (1)

[Scope of utility model registration request] 1. A starter case (4) is detachably attached to an internal combustion engine (1), and a ratchet wheel (7) is rotatable in the starter case coaxially with a crankshaft (2) of the internal combustion engine. And a flange member (15) is attached to the crankshaft, and a claw portion (10) of the ratchet wheel is drivingly connected to a centrifugal claw (16) pivotally attached to the flange member to automatically connect to the internal combustion engine. A starter (24) is provided, and the output gear (32) driven by the automatic starter is connected to the first one-way clutch device (1
1, 33) and rotatably supported on the ratchet wheel independently,
Second one-way clutch device (12,22) on the ratchet wheel
The manual starter (17) is independently rotatably supported via the motor, and the tip portion (27) of the output shaft (26) of the automatic starter is supported.
An external drive end is formed by projecting the above into the outside of the starter case, and an internal combustion engine for a portable working machine with a manual or automatic starter.